Torsion spring for counter balancing weights particularly in sectional doors

ABSTRACT

A torsion spring which is coiled or wound from spring steel wire is provided for counter-balancing weight, particularly in sectional doors. At least one of the two spring ends of the torsion spring has a connection diameter which is reduced with regard to the operational diameter of the torsion spring in a main portion between the spring ends. This connection diameter is adjusted to the outer diameter of a shaft on which the torsion spring is to be arranged in such a way that the torsion spring is guided on the shaft in a radial direction by means of any portion of the torsion spring having the connection diameter.

FIELD OF THE INVENTION

[0001] The invention relates to a torsion spring coiled or wound fromspring steel wire for counter-balancing weights. Particularly theinvention relates to a torsion spring for counter-balancing weights insectional doors. The torsion spring is to be mounted on a shaft and atleast one of the spring ends of the torsion spring has a connectiondiameter which is reduced as compared to the operational diameter of thetorsion spring between the spring ends.

BACKGROUND OF THE INVENTION

[0002] For example, torsion springs are used for counter-balancingweights in sectional doors which are used as garage and industrial doorsto an increasing extend.

[0003] The basic form of coiled or wound torsion springs forcounter-balancing weights is cylindrical. In the most simple case, sucha torsion spring has a constant diameter over its entire length from itsone spring end to its other spring end and inclusive of the spring endsthemselves, the constant diameter of the torsion spring corresponding tothe operational diameter of the torsion spring. Mounting the torsionspring to a shaft which is torsional-elastically supported by thetorsion spring is typically effected by means of a stationary fixedcone, which does not rotate with the shaft, and a tension cone arrangedon and fixed to the shaft. The respective spring end is pushed onto therespective cone, and it is, as a rule, secured to the cone by means ofclamping the wire, to which end a securing element may be formed ofspring wire at the respective end which assists in fixing the springend. Fixing the spring ends to the cones is laborious. Further, thecosts of the cones themselves are considerable, because, particularlywith cylindrical torsions springs which are matched to their respectiveuse by a variation of their operational diameter, different cones haveto be used which are matched to the respective operational diameter. Incase of cylindrical torsion springs, which are only guided by cones withregard to the shaft, there is a further problem of distortion in case oftorsional stress on the torsion spring. This distortion can becounter-acted to by a support element, which is inserted into thetorsion spring. This support element, however, is only secured withinthe torsion spring, when the torsion spring itself is built-in. Prior tothat, the support elements will easily fall out of the torsion spring.

[0004] From EP 965 399 A2 it is known to wind the spring ends with asmaller connection diameter than the operational diameter within themain portion of the torsion spring in winding a spiral shaped torsionspring, which results in a torsion spring of the type described at thebeginning. Thus it is possible to wind the spring ends with a sameconnection diameter in case of torsion springs for different loads, i.e. with different operation diameters and wire diameters, so that thesame connection elements may be used and, e.g., also a common axiallength of the torsion springs independently of their loads becomesrealizable. Adjusting the torsion springs to their respective loads isprimary effected by means of its operational diameter within the mainportion of the torsion springs between their spring ends. In case ofsuch torsion springs with reduced spring ends, however, it is difficultto support the main portion between the spring ends in a radialdirection by means of support elements. To this end, EP 965 399 A2proposes to introduce a support element in form of a tube segments intothe main portion of the torsion spring already during winding the spiralshaped torsion spring. After winding the second spring end, this supportelement is fixed within the torsion spring by means of the reducedspring ends. Introducing the supporting elements already during windingthe torsion spring is indeed very difficult. Further, there is adrawback that despite the fact that in using the torsion spring knownfrom EP 965 399 A2 the same securing element may be used independentlyof the operational diameter of the torsion spring which makes stockkeeping of the securing element more simple, securing the spring ends isstill very laborious. Concretely, the known torsion springs are stillused with cones.

[0005] In case of a torsion spring with a cylindrical diameter, it isknown to fix one spring end without using a cone. Concretely, a fixedcone is replaced in that the last winding of the spring steel wire atthe respective spring end is clamped to a plate in several spaced apartpoints, the plate, at the same time, being used for rotationallymounting the shaft on which the torsion spring is arranged and theclamping points being arranged on an arc around the rotating axis of theshaft. This known attachment allows for avoiding the fixed cone, whichreduces costs, the work effort for this kind of attachment, however, isconsiderable. Additionally, not only the attachment of the spring enditself has to be carried out in a laborious way. At the same time, thecoaxial orientation of the spring end has to be adjusted with regard tothe inner shaft.

[0006] It is an object of the invention, to disclose a torsion springfor counter balancing weights, which may be mounted with low efforts ofmaterial and work.

SUMMARY OF THE INVENTION

[0007] According to the invention, this object is achieved in that theconnection diameter of the torsion spring is matched to the outerdiameter of the torsion spring in such a way that the torsion spring isguided on the shaft by its portions having the connection diameter.

[0008] In case of the new torsion spring there is no need to coaxiallyalign the spring end having the connection diameter with the shaft bymeans of a securing element, such as a cone. The coaxial alignment isachieved between the spring end and the shaft itself in that the portionof the torsion spring having the connection diameter is guided on theshaft. This reduces the function of securing elements for the torsionspring to a fixed connection to the shaft or a stationary bearing. Axialforces, which occur between a cone and a spring end need, for example,no longer to be supported. It is possible to totally concentrate on thesupport of tangential forces. If, at the same time, shafts with astandard outer diameter are used even in case of different operationsurroundings, a very little number of different securing elements issufficient which are used independently of the operational diameter ofthe respective torsion spring. As a result, one single embodiment ofvery simple and thus low-cost securing elements can be used, the kind ofattachment rising further advantages with regard to the work efforts forthe attachment. There is no danger, however, that the torsion springunder working stress is reduced in its connection diameter up to such anextend that it jams on the shaft in an undesired way. Within theportions of the spring having the reduced connection diameter ascompared to the operational diameter, diameter reductions due to stresson the torsion spring are hardly visible.

[0009] It is to be understood, that the new torsion spring preferablyhas the connection diameter, which is reduced as compared to theoperational diameter of the torsion spring between the spring ends, atboth spring ends. In this case, use can be made of the advantages of thenew torsion spring in the new area of both end attachments.

[0010] Additionally, it is possible to reduce the torsion spring fromits connected operational diameter down to its connection diameter andto expand it again up to its operational diameter at least once betweenthe spring ends. The resulting additional portion having the connectiondiameter forms a further guiding point for the coaxial alignment of thetorsion spring with regard to the shaft.

[0011] Each portion having the connection diameter, which has theconnection diameter over at least three quarters of a full springwinding, already can exert a guiding function. It is preferred, however,that the torsion spring has the connection diameter over 1 to 5 fullspring winding within each of these portions to form a defined ringshaped and closed guidance with regard to the shaft.

[0012] Particularly, where a rotational movement takes place between thetorsion spring and the shaft, a gliding coating or a gliding sleeve canbe provided at the inside of the torsion spring in at least one portionhaving the connection diameter, the torsion spring abutting against theshaft via the gliding coating or gliding sleeve, This is no matter ofbridging sleeves, by which different connection diameters of the springends may be fitted to a shaft with a fixed outer diameter. Instead it isonly a matter of reducing the friction between the torsion spring andthe shaft.

[0013] In the new torsion spring an anchor element for taking uptangential forces can be formed of spring steel wire at at least one thespring ends. It is possible to only use this anchor element for fixingthe respective spring end as indeed only tangential forces have to besupported between the spring end and the shaft or a stationary bearing,respectively.

[0014] The anchor element made of spring steel wire can, for example, bea spring arm running tangentially to the connection diameter. It is alsopossible to have a radically or axially extending spring arm or to benda hook in one of these directions.

[0015] Within a spring arrangement, the new torsion spring is mounted ona shaft in such a way that its one spring end is fixed to the shaft andthat its other spring end is fixed to an element to which the shaft isrotationally mounted to. In other words, the other spring end of thetorsion spring is stationary.

[0016] In the following, the invention is further explained anddescribed by means of embodiment examples which are depicted in theaccompanying drawings.

SHORT DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 shows a spring end and one adjacent part of a main portionof a first embodiment of the new torsion spring in a side view onto thespring axis;

[0018]FIG. 2 shows the spring end according to FIG. 1 in a viewdirection of the spring axes, the torsion spring being arranged on ashaft;

[0019]FIG. 3 shows the whole torsion spring according to FIG. 1 in aside view onto the spring axis;

[0020]FIG. 4 shows a second embodiment of the new torsion springmodified with regard to FIGS. 1 to 3;

[0021]FIG. 5 shows one spring end of a third modified embodiment of thenew torsion spring;

[0022]FIG. 6 shows one spring end of a fourth modified embodiment of thenew torsion spring; and

[0023]FIG. 7 shows one spring end of a further modified embodiment ofthe new torsion spring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The torsion spring 3 shown in FIG. 1 in form of its spring end 1had an adjacent part of a main portion 2 is wound from spring steel wire4. Alternatively, it may be coiled from spring steel wire 4. The singlespring windings 5 of the torsion spring 3 run spirally around a springaxis 6. Within the main portion 2 the torsion spring 3 has anoperational diameter 7 by means of which, beside the spring steel wire 4and its length, the torsion spring 3 is adjusted to it respective use.This use is counterbalancing weights, to which end the torsion spring 3supports a shaft 8, depicted in FIG. 2, in a torsional-elastic way andthe shaft 3 is used for directly of indirectly taking-up holding ropesor the like of a sectional gate, for example, so that upon pulling theholding rope off the shaft 8, i.e. with increasing weight, the torsionspring 3 is torsionally stressed and exerts counter forces to theincreasing weights to be supported. To the-end of guiding the torsionspring 3, the torsion spring 3 is, for some spring windings 5 within thearea of its depicted spring end 1, reduced to a connection diameter 9which is adjusted to an outer diameter 10 of the shaft in such a way,that the spring end 1 is supported in a radial direction with regard tothe spring axis 6 by the shaft 8 in such a way that a coaxial alignmentof the torsion spring 3 on the shaft 8 is given. Within a free spacebetween the shaft 8 and the portion of the torsion spring 3 having theconnection diameter 9, a gliding sleeve 11 or another gliding means maybe provided for reducing the friction between the shaft 8 and thetorsion spring 3. A securing element for a fixed support of the springend 1 with regard to the shaft 8 or with regard to a stationary rotatingbearing for the shaft 8, which is not depicted here, does only have tofulfil the function of supporting tangential forces between the shaft 8and the torsion spring 3; to this end, an anchor element 11 made ofspring steel wire 4 is formed at the spring end 1 of the torsion springaccording to FIGS. 1 and 2, which is a spring arm 13 runningtangentially with regard to the outer diameter 6. This spring arm can befixed in a simple way to a stationary wall of a housing, for example,

[0025] Whereas FIG. 1 does not show how the respective second spring endof the torsion spring 3 is formed, FIG. 3 makes clear that both springends I have the reduced connection diameter 9, which is matched to theouter diameter of the shaft 8 (again not depicted here). However, it isalso possible, to choose another connection diameter 9 for thestationary support of one spring end, which, for example, is adjusted toa supporting ring around a rotational bearing for the shaft. This,however, is not necessary, as even in case of a torsional stress on thetorsion spring 3 there is no danger that the connection diameter 9 isreduced to such an extend that a stationary spring end jams to therotating shaft. In the area of the connection diameter 9 reduced withregard to the operational diameter 7, reductions of the diameterresulting from a torsional stress on the torsion spring only occur on astrongly reduced level so that they may be neglected in terms of guidingthe torsion spring with regard to the shaft.

[0026] Because of this, it is also possible, to reduce the diameter ofthe torsion spring 3 within its main portion 2 from its operationaldiameter 7 down to the connection diameter 9 to afterwards expand itagain up to the operational diameter 7, to form supporting portions 14by means of which the torsion spring 3 is supported at one or morepoints distributed over its length at the shaft 8 (not depicted here).In this way the coaxial arrangement of the torsion spring with regard tothe shaft is also ensured in the middle portion of the torsion spring 3without any additional supporting element.

[0027]FIG. 5 shows the spring end 1 of an embodiment of the torsionspring at which a hook 15 made of the spring wire steel 4 is formed as aanchor element 12, the hook mainly extending in parallel with the springaxis 6.

[0028] According to FIG. 6 a hook 16 is formed as an anchor element,which essentially extends radially to the spring axis 6.

[0029] According to FIG. 7 the anchor element 12 is a radially extendingspring arm 17.

1. A spiral shaped torsion spring for counter-balancing weights, saidtorsion spring being intended for being supported on a shaft and havingtwo spring ends, and a main portion between its two spring ends, saidmain portion of said torsion spring having an operational diameter, atleast one of said spring ends being a portion of said torsion springhaving a reduced connection diameter which is reduced with regard tosaid operational diameter of said main portion, wherein said connectiondiameter is adjusted to the outer diameter of the shaft so that thetorsion spring is guided on the shaft in a radial direction by means ofany of its portions having the connection diameter.
 2. The torsionspring according to claim 1, and wherein both spring ends of saidtorsion spring are portions of said torsion spring having the connectiondiameter which is reduced with regard to the operational diameter ofsaid main portion.
 3. The torsion spring according to claim 1, andwherein the torsion spring has a least one portion having the reduceddiameter within said main portion, adjacent to which at least oneportion said torsion spring is on the one side reduced from saidoperational diameter down to said connection diameter and on the otherside expanded from said connection diameter up to said operationaldiameter again.
 4. The torsions according to claim 1, and wherein eachportion of said torsion spring having the reduced connection diameterhas said connection diameter for 1 to 5 full spring windings.
 5. Thetorsion spring according to claim 1, and wherein gliding means selectedfrom a gliding coating and a gliding sleeve are arranged at the insideof said torsion spring within at least one portion having said reducedconnection diameter.
 6. The torsion spring according to claim 1, andwherein an anchor element axis is formed from the spring steel wire atleast one of said spring ends.
 7. The torsion spring according to claim6, and wherein the anchor element is a spring arm running tangentiallywith regard to the connection diameter.
 8. The torsion spring accordingto claim 6, which is for counter-balancing weights in a sectional gate.9. The torsion spring according to claim 1, which is made by coiling.10. The torsion spring according to claim 1, which is made by winding.11. The torsion spring according to claim 1, which is mounted on theshaft, one spring end of the torsion spring being fixed to the shaft andthe other spring end of the torsion spring being fixed to an element towhich the shaft is rotatingly mounted.